If you are speaking in terms of homeowners insurance then basically the replacement cost of your personal property is the cost to replace the items in your home. These would be the contents of the home. Generally replacement cost refers to how much it would cost for these items new.
How do I determine the replacement cost for personal property? The replacement cost coverage is the resale value of the property in market when sold. The resale value covers the entire rate of the land, building (with respect to age of building and its belongings) as of the market value.